YOURLS-MCP

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With no annotations provided, the description carries full burden but only states what the tool does, not how it behaves. It doesn't disclose whether this creates a permanent short URL, requires authentication, has rate limits, returns a specific format, or what happens on failure. For a write operation with zero annotation coverage, this is insufficient.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Single sentence, zero waste. Every word earns its place by conveying the core functionality efficiently. No fluff or redundant information.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a write operation (URL shortening with analytics) with no annotations and no output schema, the description is incomplete. It doesn't explain what gets returned (e.g., short URL format), error conditions, or behavioral aspects. Given the complexity and lack of structured data, more context is needed.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so the schema already documents all 8 parameters thoroughly. The description adds no additional parameter information beyond implying UTM parameters are included. Baseline 3 is appropriate when schema does the heavy lifting, though the description doesn't compensate with any extra context.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the action ('shorten') and resource ('a long URL') with the specific feature of adding Google Analytics UTM parameters. It distinguishes from sibling 'shorten_url' by mentioning analytics parameters, but doesn't explicitly contrast them. The purpose is specific and actionable.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

No guidance on when to use this tool versus alternatives like 'shorten_url' (which presumably doesn't include UTM parameters) or 'create_custom_url'. The description implies usage for tracking purposes but doesn't provide explicit when/when-not scenarios or mention sibling tools as alternatives.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.